Keywords
spondylolisthesis - spondylolysis - intervertebral disc degeneration
Palavras-chave
espondilolistese - espondilólise - degeneração do disco intervertebral
Introduction
In the evolution of humans to an upright posture, human beings have developed a pelvis
system that acts as a key structure within the locomotor system. During the course
of human development, various developmental modifications have happened around the
skeleton of the pelvis. These developments have also increased the susceptibility
to degeneration.[1] Spondylolisthesis is one such degenerative condition that occurs due to the forward
slippage of the cephalad vertebra on a caudal vertebra.[2] It is one of the common causes of lower back pain in the adult population. The treatment
of the symptomatic cases is either conservative or surgical.[3] Bone healing, pain relief, and optimization of physical activity are the three major
objectives of the management modality. Various surgical interventions are available
for management, such as posterior lumbar interbody fusion (PLIF) and anterior lumbar
interbody fusion (ALIF).[4]
[5] In 1982, a technique devised by Harms et al. was termed transforaminal lumbar interbody
fusion (TLIF), in which a bone graft filled in a titanium cage was inserted through
the transforaminal route.[6] Transforaminal lumbar interbody fusion is one such technique in which the anterior
and posterior columns are fused through a posterior approach. The anterior segment
is stabilized using a bone graft and spacer, whereas the posterior segment is stabilized
using rods, pedicle screws, and bone graft.[2] The main advantage of this technique is that it restores the disc space and maintains
the lumbar lordosis and sagittal balance. It provides another advantage of conserving
the posterior segment on the opposite side, thereby increasing the surface area for
laminal fusion. When compared with other surgical techniques, TLIF has lesser nerve
and dual damage and also provides better fusion.[7] In a study by Balasubramanian et al., clinical and radiological correlations were
performed and the study showed that 85% of the participants showed good clinical outcome
at the end of 1 year.[8] Previously available literature has shown that symptomatic lumbar spondylolisthesis
and spondylolysis can be efficiently managed by TLIF.[5]
[7]
[9]
[10] There is a gap in the available literature regarding the functional outcome of the
patient in the postoperative period. Hence, the present study was planned to fill
in this gap. The present study was performed to evaluate the functional outcome in
symptomatic lumbar spondylolisthesis and spondylolysis patients treated by TLIF using
transpedicular screws and rods.
Materials and Methods
In a tertiary care hospital, a prospective observational study was performed from
2017 to 2018. Twenty participants were enrolled in the study. Informed written consent
forms were signed and baseline clinical examination was done. Clearance of the institutional
ethical committee was obtained prior to the start of the study. Data confidentiality
was maintained. Baseline clinical and radiological evaluations were done. Patients
who had intractable pain, progressive slip, slip ≥ 25% on presentation, neurological
deficit-claudication, significant gait disturbance, cosmetic or postural disturbance,
and significant motion in dynamic X-rays were taken up for transforaminal interbody
fusion. Patients > 20 years old with isolated symptomatic lumbar spondylolisthesis
of any grade with or without spinal canal stenosis, as well as patients who were willing
to undergo surgery were included in the study. Patients with severe osteoporosis and
vertebral pathologies were excluded.
The sample size was calculated with the assumption of an expected mean difference
in the outcome before and after intervention of 5.3 and a standard deviation of 4.5
according to the previous study by Reddy et al.[1] The power of the study was kept at 90% with a 5% two-sided α error. The sample size
was determined by using the formula as proposed by Kirkwood et al.[11] The required sample size, according to the aforementioned calculation, was 16. To
make up for a nonparticipation rate of ∼ 30%, 3 participants were added to the sample
size. Hence, the total sample size was 19 subjects.
Both anteroposterior and lateral films were taken. When slippage or pars defect was
not clear, oblique (45° angled) radiographs were taken. In high-grade spondylolisthesis,
the slippage appears as ‘invented Napoleon's hat’, and in pars defect, the ‘Scottie
dog’ pattern is seen.
Transpedicular Screw Placement
For the entry point into the lumbar pedicle, the Roy-Camille technique was used. In
the Roy-Camille method, the location of the entry point is by the intersection of
the midtransverse process line and the superior facet midline. These bony landmarks
are easily identified during surgery. The entry points were identified under C-Arm
guidance, and screws were placed through the pedicle into the body. Monoaxial and
polyaxial screws were used for instrumentation. Sacral screws were placed parallel
to the sacral endplate with bicortical purchase. Unilateral laminectomy and unilateral
facetectomy were performed. Using an intervertebral distractor and a nerve root distractor,
the disc was approached through the transforaminal route, and complete discectomy
was performed. Endplates were thoroughly scraped. The adequate reduction was attempted
by distraction after placing the titanium rod, and the upper body was moved in a cranial
and posterior direction by rotatory movements. The spinous process and lamina bone
graft were made into small pieces and placed in the interbody space so that they fit
snugly in the titanium cages placed in the interbody space. The closure was performed
in multiple layers-paraspinal muscle fascia and subcutaneous tissue with Vicryl and
skin with Ethilon under a negative suction drain. The preoperative and postoperative
comparison was made of the various study parameters.
The visual analogue scale (VAS) and the Oswestry Disability Index (ODI) were the primary
outcome measures used. Preoperative measurements were corroborated with postoperative
measurements and compared with the effectiveness of the surgery.
Statistical Methods
The primary outcome variables were the VAS, the ODI, slip percentage, and disc height
at follow-up. Age, gender, duration of symptoms, complications, etc., were kept as
other relevant variables. The description of the data was represented by mean and
standard deviation (SD). Statistical significance was considered with p < 0.05. coGuide (BDSS CORP, Bangalore, Karnataka, India) version V.1.0 statistical
software was used.
Results
Twenty patients were included for the final analysis.
Among the study subjects, the mean age was 48.25 ± 5.35 years old, ranging from 22
59 years old. Regarding the duration of symptoms, 11 (55%) patients had symptoms for < 36
months and 9 (45%) of them had symptoms for ≥36 months; 20 (100%) of them had lower
back pain, 14 (70%) had radiculopathy, 7 (35%) had claudication, and 11 (55%) had
comorbid conditions. Regarding the level of slippage, 11 (55%) had L5-S1, and 9 (45%)
had L4-L5. Regarding the grade of slippage, 14 (70%) had grade 2, and 5 (25%) had
grade 3 ([Table 1]).
Table 1
Descriptive analysis of baseline parameters in the study population (n = 20)
|
Parameter
|
Summary statistics
|
|
Age (years old)
|
48.25 ± 5.35 (22–59)
|
|
Age (years old)
|
|
|
30–40
|
01 (5%)
|
|
41–50
|
10 (50%)
|
|
51–60
|
09 (45%)
|
|
Gender
|
|
|
Male
|
09 (45%)
|
|
Female
|
11 (55%)
|
|
Type of spondylolisthesis
|
|
|
Degenerative
|
12 (60%)
|
|
Isthmic
|
7 (35%)
|
|
Traumatic
|
1 (05%)
|
|
Duration of symptoms (months)
|
|
|
< 36 months
|
11 (55%)
|
|
≥ 36 months
|
9 (45%)
|
|
Lower back pain - present
|
20 (100%)
|
|
Radiculopathy - present
|
14 (70%)
|
|
Claudication - present
|
7 (35%)
|
|
Comorbid conditions - present
|
11 (55%)
|
|
Level of slip
|
|
|
L4-L5
|
09 (45%)
|
|
L5-S1
|
11 (55%)
|
|
Grades of slip
|
|
|
Grade 1
|
01 (5%)
|
|
Grade 2
|
14 (70%)
|
|
Grade 3
|
05 (25%)
|
|
Spacer
|
|
|
Bone graft
|
15 (75%)
|
|
Titanium cage
|
05 (25%)
|
|
Fusion
|
|
|
Fusion
|
18 (90%)
|
|
Pseudo arthroses
|
02 (10%)
|
|
Rate of fusion
|
4.85 ± 2.05 (1–8)
|
|
Complications
|
|
|
Implant related
|
01 (5%)
|
|
Infection
|
02 (10%)
|
|
Others
|
03 (15%)
|
|
No complications
|
14 (70%)
|
Among the study population, the mean preoperative VAS score was 7.50 ± 1.05, and the
mean postoperative VAS score was 2.20 ± 1.19. The mean difference in the VAS score
between the two periods was statistically significant, (p < 0.001). The mean difference for ODI, slip percentage, and disc height between the
two periods was statistically significant, with a high preoperative ODI of 59.11 ± 8.65
compared with a postoperative ODI of 33.10 ± 9.69 (p < 0.001), ([Table 2]).
Table 2
Comparison of outcome parameters between the preoperative and postoperative periods
(n = 20)
|
Parameter
|
Periods
|
p-value
|
|
Preoperative
|
Postoperative
|
|
VAS
|
7.50 ± 1.05
|
2.20 ± 1.19
|
< 0.001
|
|
ODI
|
59.11 ± 8.65
|
33.10 ± 9.69
|
< 0.001
|
|
Slip percentage
|
44.65 ± 15.01
|
18.75 ± 7.52
|
< 0.001
|
|
Disc height
|
8.96 ± 0.17
|
10.69 ± 0.18
|
< 0.001
|
Abbreviations: ODI, Oswestry Disability Index; VAS, visual analogue scale.
Discussion
The most common spondylolisthesis type among the study participants was degenerative.
Although many procedures exist for the management of spondylolisthesis, achieving
disc stability and postoperative pain reduction is the main aim of performing a procedure.
Transpedicular screw fixation with interbody fusion is one of the procedures with
advantages such as high fusion rate, early postoperative mobilization of the patient,
and lack of need for orthoses postoperatively.[1] The foremost findings of the present study were that the mean difference in the
VAS between the preoperative and postoperative periods was statistically significant
(p < 0.001), and that the mean difference in the ODI, slip percentage, and disc height
between the preoperative and postoperative period were also statistically significant
(p < 0.001).
In the present study, most prevalent age group ranged from 41 to 50 years old. Degenerative
spondylolisthesis was the most common among the study participants. Similar findings
were observed by Reddy et al.[1] in whose study the most commonly affected group was in the range between 40 and
50 years old. In the present study, the most common type of spondylolisthesis was
degenerative, followed by isthmic and traumatic. Similar findings were also observed
by Soren et al.,[9] in whose study 62.4% of the participants had degenerative spondylolisthesis. In
the present study, 55% of the participants had a level of slippage at L5-S1. A similar
level of slippage was observed by Vekatesh et al.[1] and Kalichman et al.[10] In these two studies, the slippage level at L5-S1 was due to degenerative spondylolisthesis,
whereas in isthmic listhesis the slippage level L4-L5. Invariably, all participants
of the present study had lower back pain, similar to other studies.[13]
[14] In a study by Möller et al.,[15] 62% of the study participants had lower back pain with sciatica. Most commonly,
spondylolisthesis presents with two types of symptoms. The back symptoms, like lower
back pain, are caused due to mechanical pain, and the patient will feel better with
fixation, whereas the leg symptoms, such as sciatica, tingling, and numbness caused
due to nerve compression, will respond well to a decompression procedure. Ironically,
the back pain of the spondylolisthesis disappears once there occurs spontaneous fusion
of the spondylolisthesis segment. The leg symptoms associated with spondylolisthesis
is caused due to canal compromise caused due to disc prolapse and also due to ligamentum
flavum hypertrophy. The relief of these symptoms can be achieved by wide decompression.
In all study participants, wide laminectomy and discectomy were performed to achieve
adequate decompression.
Despite the available evidence, the management of lumbar spondylolisthesis remains
controversial due to lack of absolute success by any single modality. There are several
other techniques, such as anterior interbody fusion (ALIF), extreme lateral interbody
fusion (XLIF), and posterolumbar interbody fusion (PLIF). Achieving symptomatic relief
from pain, removal of neurological defects, and improving stability remains the main
objectives of treatment. Transforaminal lumbar interbody fusion with transpedicular
screws and rods has been successful in producing a functional outcome postoperatively.
In the present study, there was a statistically significant difference in the VAS,
the ODI. slip percentage, and disc height in the preoperative and postoperative periods.
This indicates that the operative procedure has addressed the aforementioned objectives.
Similar efficacy and functional outcomes have been documented in previous literature.[1]
[2]
[13]
[14] The present adds evidence to support that TLIF with transpedicular screws and rods
provides the best functional outcome.
The limitation of the present study was that it was based on a small sample from a
single center. Multicentric studies comparing the efficacy of other treatment modalities
in the management of spondylolisthesis and spondylolysis are recommended in the future.
Conclusion
Transformational interbody lumbar fusion with transpedicular screws and rods is a
safe and effective management option for degenerative spondylolisthesis and spondylosis.
It provides a good functional outcome through pain relief and improves quality of
life.
